1. Field of the Invention
The present invention relates to an image display controller, an image pickup apparatus, a method of controlling the image display controller, and a storage medium storing a control program for implementing the method, and more particularly to a technique for displaying information indicative of a specific area of an image.
2. Description of the Related Art
In general, an image pickup apparatus, such as a digital camera, is configured to detect a specific area of an image (e.g. a specific area of an object) for image pick up. Further, this type of image pickup apparatus is provided with an image display controller for displaying information (specific area information) indicative of a specific area of an image on a display device.
For example, there is proposed an image pickup apparatus which is provided with a face detecting section for detecting a face area (specific area) of an object and causes the image display controller to display a display frame (display information) indicative of the face area detected by the face detecting section on the display device (see Japanese Patent Laid-Open Publication No. 2007-274207).
In Japanese Patent Laid-Open Publication No. 2007-274207, the image display controller changes attributes (e.g. display frame color and shape) of the display frame indicative of the detected face area according to a feature value (e.g. a face angle) of the face of the object, and then displays the changed display frame on the display device. This enables the user to intuitively perceive the face feature of the object.
Further, there has been proposed an image pickup apparatus, such as a monitoring camera, provided with a human body-detecting section for detecting a human body portion (human body area) of an object, in addition to a face detecting section for detecting the face area of an object.
FIG. 35 is a view illustrating how a face display frame and a human body display frame are displayed in the conventional image pickup apparatus provided with the face detecting section and the human body-detecting section. As shown in FIG. 35, a face display frame 2010 corresponding to the face area of an object and a human body display frame 2020 corresponding to the object are displayed on a screen 2000 of a display device. The human body display frame 20200 contains the face display frame 20100 as shown in FIG. 35.
In the conventional image pickup apparatus provided with the face detecting section and the human body-detecting section, however, a face display frame and a human body display frame are displayed on the display device independently of each other. For this reason, when the human body-detecting section is configured to detect an area having a human figure shape including a head portion, the face display frame is displayed in a manner included in the area of the human body display frame (i.e. in a manner overlapping the area of the human body display frame).
When the face display frame is displayed in a manner overlapping the area of the human body display frame as mentioned above, the visibility of the face display frame and the human body display frame for the user, particularly the visibility of the human body display frame lowers.
FIG. 36 is a view illustrating how the face display frame 2010 and the human body display frame 2020 change in the conventional image pickup apparatus when zoom magnification is changed in a state where the face display frame 2010 and the human body display frame 2020 are consecutively displayed.
As shown in FIG. 36, when zoom magnification is changed from the telephoto end to the wide-angle end, the face display frame 2010 and the human body display frame 2020 both become smaller as the size of the object is reduced. As a consequence, particularly in a wide-angle state, the object is hidden by the frames, and the visibility of the frames and the object lowers.
Now, a description will be given of a case where a plurality of frames are consecutively displayed.
FIG. 37 is a view illustrating how the face display frame and the human body display frame of the object in the image shown in FIG. 35 are displayed as frames of image data are changed.
In FIG. 37, it is assumed that the face display frame 2010 and the human body display frame 2020 are displayed on the display device as described with reference to FIG. 35. For example, when a difference (change) occurs in a feature value of the human body display frame 2020 as the frame of image data is changed, the face display frame 2010 contained in the human body display frame 2020 is sometimes displayed in a manner shifted in one direction though there is no change in the relative position between the face and the human body.